Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Acknowledgment is made of applicant’s claim for foreign priority (SG10202101091U, filed on 02 February 2021) under 35 U.S.C. 119 (a)-(d). Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over WAN et al. (US20200298185A / WO2019108136A1, hereinafter WAN).
Regarding Claim 1, WAN discloses a thin film composite hollow fiber membrane (¶[0001]). The membrane includes a porous hollow fiber support layer formed from sulfone-based polymers, such as polyethersulfone, polysulfone, or related materials, and a cross-linked polyamide selective layer on the inner circumferential surface of the support layer (¶¶[0040]–[0042]). The cross-linked polyamide selective layer provides water transport and ion rejection, with high pure water permeability, low salt permeability, and high salt rejection rate (¶¶[0049]–[0052]).
In Table 3, PES hollow fiber substrates had measured burst pressures of 28 bar, 33 bar, and greater than 35 bar at a dope-to-bore-fluid flowrate ratio of 3. Burst pressure increases with tensile strength and is related to wall thickness, tensile stress, and outer diameter under Barlow’s equation (¶[0107]). The disclosed burst pressure greater than 35 bar (>3.5 MPa) provides an open-ended burst-pressure disclosure that encompasses the claimed “internal burst pressure of at least 4 MPa.”
Regarding Claim 2, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. WAN discloses that the thin film composite hollow fibre membrane comprises a porous hollow fibre support layer and a selective layer on an inner circumferential surface of the hollow fibre support layer (¶¶[0009]–[0011]).
Regarding Claim 3, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. WAN discloses the porous hollow fiber support layer is formed from sulfone-based polymers, including polyethersulfone or polysulfone (¶¶[0040]–[0042]).
Regarding Claim 4, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. WAN discloses forming the selective layer on the inner circumferential surface of the hollow fiber support layer through interfacial polymerization with a polyamine and a polyfunctional acyl halide (¶[0056]).
Regarding Claim 5, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. WAN discloses the porous hollow fiber support layer has a sponge-like porous structure based on the dope solution composition (¶[0074]) and a finger-like macrovoid structure (¶[0080]).
Regarding Claim 6, WAN makes obvious the thin film composite hollow fiber membrane of Claim 5. WAN discloses PES hollow fiber substrates with a dual layer finger-like macrovoid structure having a thicker or longer inner macrovoid layer, and the two layers of uniform macrovoids provide strong mechanical support against the applied pressure and render open channels for water transport (¶[0112]).
Regarding the limitation “the thickness of the finger-like macrovoid region is no greater than 70% of the wall thickness,” this limitation is considered a result-effective variable as it recites the relative thickness of the known finger-like macrovoid region within the known wall thickness. Since WAN discloses that the macrovoid structure affects mechanical support and water transport, it would have been obvious to a person skilled in the art to optimize the relative thickness of the finger-like macrovoid region to achieve a predictable balance of mechanical support and water transport.
Regarding Claims 7 and 8, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. Table 3 of WAN shows PES hollow fiber substrates with measured burst pressures of 28 bar, 33 bar, and greater than 35 bar at a dope-to-bore-fluid flowrate ratio of 3 (¶[0107]).
Regarding the limitations “the internal burst pressure is at least 7 MPa” and “at least 10 MPa,” the claimed values are higher optimized thresholds of the known internal burst-pressure property. WAN discloses a highly similar thin film composite hollow fiber membrane structure and composition, reports an open-ended burst pressure greater than 35 bar (>3.5 MPa), and identifies tensile strength, wall thickness, tensile stress, and outer diameter as parameters related to burst pressure. Thus, it would have been obvious to a person skilled in the art to optimize those known mechanical parameters to increase internal burst pressure, achieving the predictable result of improved pressure resistance.
Regarding Claim 9, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. WAN discloses the selective layer is formed of cross-linked polyamide and has a thickness of 100–500 nm (¶¶[0040]–[0042]). The disclosed thickness range falls within the claimed “between 100 and 600 nm.”
Regarding Claim 10, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. Table 4 of WAN shows PES hollow fiber substrates having outer diameters of 1064–1081 µm (¶[0112]). The disclosed outer-diameter range falls within the claimed “between 800 and 1200 µm.”
Regarding Claim 11, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. WAN discloses the hollow fibre support layer has a thickness of 100–500 µm (¶[0009]), and Table 4 shows PES hollow fiber substrates having outer diameters of 1064–1081 µm (¶[0112]). Using the relationship ID = OD − 2 × wall thickness, the disclosed outer-diameter and wall-thickness ranges encompass inner diameters within the claimed “between 150 and 500 µm.”
Regarding Claims 12 and 13, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. WAN discloses the hollow fibre support layer has a thickness of 100–500 µm (¶[0009]). The disclosed thickness range overlaps the claimed “wall thickness of at least 250 µm” and “wall thickness of at least 350 µm.”
Regarding Claim 14, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. Table 4 of WAN shows PES hollow fiber substrates having porosities of 71.7–74.1% (¶[0112]). The disclosed porosity range falls within the claimed “between 55% and 80%.”
Regarding Claim 15, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. Table 3 of WAN shows PES hollow fiber substrates having tensile strengths of 5.85 MPa and 6.44 MPa at a dope-to-bore-fluid flowrate ratio of 3 (¶[0107]). The disclosed tensile-strength values fall within the claimed “maximum tensile stress of at least 5.5 MPa.”
Regarding Claim 16, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. The claimed “Young's Modulus of at least 170 MPa” is an optimized threshold of the known stiffness property of the hollow fiber support. WAN discloses a highly similar sulfone-based hollow fiber support layer evaluated for tensile strength and burst pressure, and burst pressure increases with tensile strength and is related to wall thickness, tensile stress, and outer diameter (¶¶[0040]–[0042], [0107]). Since stiffness is tied to the composition and porous structure of the hollow fiber support, it would have been obvious to a person skilled in the art to optimize the support-layer composition and structure to provide a Young's Modulus at or above the claimed 170 MPa threshold, achieving the predictable result of improved stiffness and pressure resistance.
Regarding Claim 17, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. Table 5 of WAN shows TFC-PES hollow fiber membranes having structural parameter S values of 422–457 µm, i.e., 0.422–0.457 mm (¶[0117]). The disclosed structural parameter range falls within the claimed “below 0.9 mm.”
Regarding Claim 18, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. Table 5 of WAN shows TFC-PES hollow fiber membranes having pure water permeability A values of 3.3–3.8 LMH/bar (¶[0117]). The disclosed permeability values correspond to 33–38 LMH/MPa, which are above the claimed “at least 25 LMH/MPa.”
Regarding Claims 19 and 20, WAN makes obvious the thin film composite hollow fiber membrane of Claim 1. Table 5 of WAN shows TFC-PES hollow fiber membranes having NaCl rejection rates of 95.3–97.3% (¶[0117]). The disclosed rejection values are above the claimed “at least 90%,” and include a rejection rate of 97.3%, which is above the claimed “at least 97%.”
Response to Arguments
Applicant’s arguments, see Remarks filed on March 28, 2026, have been fully considered but are not persuasive. The statutory basis of the rejection of Claims 1–20 under 35 U.S.C. § 103 is maintained, and the rejection is updated over WAN. Upon further consideration, KLEIN is not relied upon in the current rejection.
Applicant’s arguments directed to KLEIN have been considered but are moot because KLEIN is not relied upon in the current rejection. Applicant’s arguments concerning KLEIN’s external pressure/collapse resistance, KLEIN’s different membrane structure, and the proposed combination of WAN with KLEIN do not address the basis of the current rejection. The current rejection relies on WAN’s thin film composite hollow fiber membrane structure, open-ended burst-pressure disclosure, and disclosed mechanical parameters affecting burst pressure.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAK L. CHIU whose telephone number is (703)756-1059. The examiner can normally be reached M-F: 9:00am - 6:00pm (CST).
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, PREM C. SINGH can be reached at (571)272-6381. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/TAK L. CHIU/Examiner, Art Unit 1777
/KRISHNAN S MENON/Primary Examiner, Art Unit 1777
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